When Maureen Evans goes up to the concession counter to order her popcorn and Pepsi, the clerk gives it to her without accepting any money, or ringing it up on the till, yet we see her with the money in her hand.
SPOILER: During the last stabbing of Maureen Evans, the killer puts his right arm around her and stabs her with his left, but from the back view, his left arm is around her and he is stabbing her with his right hand.
The position of Sidney’s head near the end of her first conversation with Dewey in the gazebo.
When Sid smacks Gail Weathers in the courtyard after being introduced to Cotton for the first time, Gail’s hair alternates between being tucked behind her ears and being in her face in between shots.
While Cici is running away from the killer, she makes her way to the second floor, where the killer is right behind her, yet in the next scene, she is far ahead of him.
SPOILER: After Cici is thrown through the window and is lying on the balcony, you can see blood on her back before she is stabbed.
SPOILER: In the scene where the killer is after CiCi on the balcony, the killer stabs her in the back twice but when the killer removes the knife from her back both times you can clearly see there is no blood on it.
When Sidney is rehearsing in the play as Cassandra, after she gets up, in one shot she is covering her face with her veil and in the next shot, she has her arms and her veil up and she is lowering them.
When the killer talks to Randy on the phone, he mocks Randy about not being the leading man, to which Randy replies “Fuck You!” But when Gale and Dewey watch the killer’s tape, Randy says “Fuck You!” before the killer mocks him.
SPOILER: When Randy is being stabbed in the news van, the blood on the knife stays the same each time he gets stabbed.
SPOILER: When Sidney and Hallie get in the police escort car Hallie gets in first sitting on the left, but later when the car is driving down the street and eventually crashes, Sidney and Hallie have switched places and Sidney is now on the left. (This was explained in an outtake. As a joke, the girls got out and ran around the car when it stopped at a red light.)
Sidney has a zit on her chin toward the end of the movie, when she gets into the car. But in the climax, it isn’t there.
The police chief conducts a press conference. Later, when videotape of the press conference is reviewed by Gale, the person to his left (frame right) is different.
When Gale kisses Dewey in the lecture theatre, all her dark red lipstick is wiped off or smeared around her mouth, but none of it appears on Dewey.
When Dewey is pounding on the soundproof glass, trying to get Gale’s attention, his hand alternates between being open palmed and balled in a fist.